Body mass index and cancer mortality in patients with incident type 2 diabetes: A population‐based study of adults in England

• Published in: Diabetes, obesity & metabolism Vol. 24; no. 4; pp. 620 - 630
• Main Authors: Alam, Nasra N., Wright, Alison K., Rutter, Martin K., Buchan, Iain, Ashcroft, Darren M., Sperrin, Matthew, Renehan, Andrew G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.04.2022; Wiley Subscription Services, Inc
• Subjects: Adult; Aged; Aged, 80 and over; BMI; Body Mass Index; Cancer; Cardiovascular diseases; Cardiovascular Diseases - complications; Diabetes; Diabetes mellitus (non-insulin dependent); Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - epidemiology; Endometrium; Female; Humans; Male; Middle Aged; Mortality; Neoplasms - complications; Neoplasms - epidemiology; Obesity; Obesity - complications; Obesity - epidemiology; Patients; Population studies; Population-based studies; Risk Factors; Smoking; type 2 diabetes; mortality; cancer; type 2 diabetes; obesity; BMI
• DOI: 10.1111/dom.14614
• ISSN: 1462-8902

Aims We evaluated the relationship between body mass index (BMI) and cancer mortality in incident type 2 diabetes. Methods We used the Clinical Practice Research Datalink GOLD (1998‐2015), linked with the Office of National Statistics mortalities, and derived an incident type 2 diabetes cohort (N = 176 886; aged 30‐85 years). We determined BMI ±12 months diabetes diagnosis. The primary outcome was cancer mortality, categorized into deaths from obesity‐related cancers (ORCs) and non‐ORCs. Secondary outcomes were site‐specific cancer mortality and main causes of deaths [cancer, cardiovascular disease (CVD), non‐cancer non‐CVD]. We developed gender‐specific Cox models and expressed risk as hazard ratios and 95% confidence intervals, stratified by smoking status. Results With 886 850 person‐years follow‐up, 7593 cancer deaths occurred. Among women who never smoked, there were positive associations between BMI and deaths from endometrial (hazard ratios per 5 kg/m2: 1.43; 95% confidence interval 1.26‐1.61). Among men, associations between BMI and ORC mortality were inverse but attenuated towards null among never smokers and excluding deaths in the first 2 years. In men, the proportion of CVD deaths increased from 36.8% in BMI category 22.5 to 24.9 kg/m2 to 43.6% in BMI category ≥40 kg/m2 (p < .001). Conclusions We found some relationships between BMI and cancer mortality in patients with type 2 diabetes, but interpretations need to account for smoking status, reverse causality and deaths from CVD.